client_getFormattedNumber

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden of behavioral disclosure. It only says 'Get', implying a read operation, but does not describe what formatting is applied, whether it depends on locale/country, or what the return value looks like. There is no mention of potential side effects or required permissions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single sentence with no wasted words, making it concise and front-loaded. However, it is under-specified, which prevents a perfect score. It is appropriately sized for a simple get operation but lacks necessary context.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple (2 params, no nested objects), but there is no output schema, so the description should explain the return value. It does not. The ambiguity around 'formatted number' and lack of sibling differentiation make the description incomplete for effective selection and invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description itself adds no extra meaning beyond the schema fields. Both parameters have brief descriptions in the schema, but the tool description contributes nothing additional.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Get the formatted number' states a clear verb and resource, but the resource is vague—it doesn't specify what number is being formatted or what 'formatted' means. There is a sibling tool contact_getFormattedNumber, and the description does not distinguish itself from that alternative.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided on when to use this tool versus alternatives like contact_getFormattedNumber. The description lacks any context about typical use cases, prerequisites, or conditions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.